"Dunkleosteus: this was a terrifying armoured fish of the Late Devonian era that could grow up to 6m in length. The skull was armoured and although some models show this as exposed bone plates, the CollectA model correctly shows it covered with skin. It did not possess teeth but had bone shears instead. As only the bone skull survives in the fossil record as the rest of the body was made of cartilage therefore, the rest of the body is based on other smaller and related species. The new model adopts the idea that such a huge fish would have had to have had a heterocercal caudel fin rather like the shark in order to efficiently manoeuvre around. The CollectA replica comes with a movable jaw."